Perfecting web rotary offset printing press with slanted units



A ril 13, 1965 w. KOCH 3,177,804

PERFECTING WEB ROTARY OFFSET PRINTING PRESS WITH SLANTED UNITS Filed Sept. 11, 1963 United States Patent 3 177 804 PERFECTING WEB nb'riiRY OFFSET PRHJTING PRESS WITH SLANTED UNITS Werner Koch, Offenbach (Main), Germany, assignor to Roland Offsetmaschinenfabrik Faber & Schieicher A.G., Otfenbach (Main), Germany, a German body corporate Filed Sept. 11, 1963, Ser. No. 308,211

Claims priority, application Germany, Nov. 17, 1962,

33, 4 Claims. (Cl. 101177) The invention relates to roll-fed offset printing presses and, more particularly, to roll-fed offset printing presses in which the axes of the two blanket cylinders and the axes of the two plate cylinders are disposed in two parallel planes.

It is conventional with offset presses of the general kind above-referred to guide the paper web on which printing is to be effected normal to the parallel planes in which the cylinders are disposed. As a result the paper web is tangential to the peripheries of the blanket cylinders when it passes between the same. Such an arrangement has the disadvantage that the paper web is not positively guided when the gaps of the two blanket cylinders in which the clamping mechanism for the blankets is accommodated, are in registry in the printing zone. Furthermore, there is the danger that the paper will be torn when the peripheral surfaces of the two blanket cylinders meet again.

It has already been proposed to avoid these disadvantages by guiding the paper web first between one of the blanket cylinders and a counter cylinder, whereby one side of the paper is printed. The paper web is then guided between the two blanket cylinders whereby the other side of the paper web is printed with the image on the second blanket cylinder. In such an arrangement one side of the paper web is subjected twice to pressure and furthermore, remains in contact with the respective blanket cylinder for a considerably longer time than the other side of the paper web. As a result the conditions for transferring ink or color dye are markedly different for the two sides of the paper web so that the appearance of the printed matter may be quite different on the two sides of the paper web which makes the arrangement unsuitable for quality work. Furthermore, the provision of an additional pressure cylinder or roll and of control devices for such additional component causes a substantial increase of the costs of the press.

It is a broad object of the present invention to provide a novel and improved roll-fed offset printing press of the general kind above referred to in which the paper web is positively guided also when the gaps in the blanket cylinders pass through the common printing zone defined by the blanket cylinders.

A more specific object of the invention'is to provide a novel and improved roll-fed ofisct printing machine in which the afore-referred to tangential passage of the paper web between the blanket cylinders is replaced by imparting to the paper web a limited wrap-around or S-shaped pattern when the paper passes between the blanket cylinders. As a result of such limited wrap-around or S- shaped pattern the paper web remains in positive contact with peripheral surface portions of both blanket cylinders even when the gaps in these cylinders pass the printing zone, thus assuring a continuous positive guiding of the paper web in the printing zone.

Another more specific object of the invention is a novel and improved roll-fed offset printing press in which the aforementioned limited wrap-around or S-shaped pattern of the paper web when passing between the blanket cylinders is attained in a very simple and convenient manner by arranging the two parallel planes in which the cylinders of the press are disposed at a slant in reference to the plane of travel of the paper web so that the planes of the cylinders define an acute angle with the plane of the paper web,

Still another more specific object of the invention is to provide a novel and improved roll-fed offset printing press in which the aforementioned angular relationships of the planes of the cylinders and the plane of the paper travel is obtained by mounting the frame structure of the press at a slant in reference to a horizontal base and guiding the paper web along a horizontal path. All the conventional components of a printing press such as dampening rolls and inking rolls may be retained unchanged and no additional control devices are required. In particular, the conventional symmetric mounting of the cylinders and the bearings therefor may be retained.

Other and further objects, features and advantages of the invention will be pointed out hereinafter and set forth in the appended claims constituting part of the application.

In the accompanying drawing a preferred embodiment of the invention is shown by way of illustration and not by way of limitation:

In the drawing:

FIG. 1 is an elevational diagrammatic view of a conventional roll-fed offset printing press, and

FIG. 2 is a diagrammatic elevational view of a printing press of the type shown in FIG. 1, but modified in accordance with the invention.

Referring first to FIG. 1, the press shown in this figure comprises a symmetric couple of two printing units mounted on a common base 1. Each unit comprises an upright frame structure 2 in which the two blanket cylinders 3 and two plate cylinders 4 are mounted in a suitable and conventional manner. The blanket cylinders should be visualized as being of conventional design, that is a blanket such as a rubber blanket envelops the cylinder proper and is secured by a clamping mechanism (not shown) accommodated in a lengthwise gap 10. The rates of rotation of the blanket cylinders may be so adjusted that the gaps are in registry when they pass through the printing zone. Dampening rolls 5 and inking rolls 6 are diagrammatically indicated. The term inking rolls is intended to encompass both, black and white printing and color printing. The press should be visualized as being equipped with conventional control and adjustment means. These means are not shown as they do not constitute part of the invention.

The plate cylinders 4 are disposed in a common plane A and the blanket cylinders 3 in a common plane B. Both planes are parallel to each other.

The paper web 7 is guided from a conventional web roll (not shown) along a rectilinear path between the two pairs of blanket rolls 3. Guide rolls as usually employed with presses of the kind here involved are diagrammatically indicated at 11.

As it is shown in FIG. 1, planes A and B are normal to the plane of the paper web. Accordingly, the web will pass between the blanket cylinders in tangential relationship. The web when passing the area of contact between the two blanket cylinders is being printed on both sides.

The press according to the invention, as shown in FIG. 2, has basically the same structure as the press according to FIG. 1 and the same reference numerals are used to designate thecorresponding components. However, in the press according to FIG. 2 the planes of the cylinders are not normal to the plane of the paper Web, but define an acute angle with the plane of the paper web. In other words, the frame structure of the couple of the press is slanted in reference to the paper web. Such Patented Apr. 13, 1965 I slant of the frame structure can be attained in a simple manner and also for an existing press by fitting wedgeshaped inserts 8 between base 1 and the frame structure 2. As a result of such simple change in the press structure the paper web no longer passes between the blanket cylinders in tangential relationship but with a limited wrap-around of the web about the peripheral surface of each of the blanket cylinders. In other Words, the web will engage the peripheral surface of the upper blanket cylinder 3 just before the peripheral surfaces of the two blanket surfaces engage each other and the paper web will remain in contact with the peripheral surface of the lower blanket cylinder for a short period after the peripheral surfaces of the two blanket cylinders become separated, thus imparting to the paper web an S-shaped pattern when passing between the blanket cylinders. As a result of such limited wrap-around or S-shaped pattern, the paper web will bridge the edges of gaps 10 in the cylinders whereby it is positively guided at all times when passing between the blanket cylinders.

While the invention has been described in detail with respect to a certain now preferred example and embodiment of the invention, it will be understood by those skilled in the art, after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended therefore to cover all such changes and modifications in the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A web fed rotary oltset printing press comprising a pair of plate cylinders disposed in a common plane, a pair of blanket cylinders coacting with the plate cylinders and each other and disposed in a second common plane parallel'to the first plane, and guide means for guiding a paper web along a rectilinear path and between the blanket cylinders, said parallel planes being oriented. to

define an acute angle with said path of the paper web 2. A web fed rotary offset printing press comprising a frame structure, a pair of plate cylinders mounted on said frame structure with the rotational axes of the cylinders disposed in a common plane, a pair of blanket cylinders mounted on said frame structure in cooperating relationship with each other and the plate cylinders, the axes of the blanket cylinders being disposed in a second common plane parallel to the first plane, and guide means for guiding a paper web along a rectilinear path and between the blanket cylinders, said parallel planes of the cylinders defining an acute angle with said path of the web, whereby an S-shaped pattern is imparted to the paper web when passing between the blanket cylinders.

3. A web fed rotary offset printing press comprising a frame structure, a pair of plate cylinders mounted on said frame structure with the rotational axes of the cylinders disposed in a common plane, a pair of blanket cylinders mounted on said frame structure in cooperating relationship with each other and the plate cylinders, the axes of the blanket cylinders being disposed in a second common plane parallel to the first plane, said frame structure being slanted in reference to a horizontal base, and guide means for guiding a paper Web to be printed along a horizontal path and between the blanket cylinders, said common planes of the cylinders defining an acute angle with said horizontal path of the paper web whereby an S-shaped pattern is imparted to the paper web when passing between the blanket cylinders.

4. A web fed rotary offset printing press according to claim 3 wherein wedge-shaped inserts are fitted between a horizontal support base and'said frame structure to slant the latter in reference to said base.

References Cited by the Examiner UNITED STATES PATENTS 1,028,485 6/12 Pancoast 101-180 2,859,691 11/58 Heller 101-177 2,875,688 3/59 Steyer 101-180 EUGENE R. CAPOZIO, Primary Examiner. 

1. A WEB FED ROTARY OFFSET PRINTING PRESS COMPRISING A PAIR OF PLATE CYLINDERS DISPOSED IN A COMMON PLANE, A PAIR OF BLANKET CYLINDERS COACTING WITH THE PLATE CYLINDERS AND EACH OTHER AND DISPOSED IN A SECOND COMMON PLANE PARALLEL TO THE FIRST PLANE, AND GUIDE MEANS FOR GUIDING A PAPER WEB ALONG A RECTILINEAR PATH AND BETWEEN THE BLANKET CYLINDERS, SAID PARALLEL PLANES BEING ORIENTED TO DEFINE AN ACUTE ANGLE WITH SAID PATH OF THE PAPER WEB WHEREBY AN S-SHAPED PATTERN IS IMPARTED TO THE PAPER WEB WHEN PASSING BETWEEN THE BLANKET CYLINDERS. 